Whakaoti i te 4x^2+4x=5

$$4 x ^ { 2 } + 4 x = 5$$

Whakaoti mō x

$$x=\frac{\sqrt{6}-1}{2}\approx 0.724744871$$

$$x=\frac{-\sqrt{6}-1}{2}\approx -1.724744871$$

Ngā Upane e Whakamahi ana i te Tikanga Tātai Pūrua

Ko ngā whārite katoa o te āhua ax^{2}+bx+c=0 ka taea te whakaoti mā te whakamahi i te tikanga tātai pūrua: \frac{-b±\sqrt{b^{2}-4ac}}{2a}. E rua ngā otinga ka puta i te tikanga tātai pūrua, ko tētahi ina he tāpiri a ±, ā, ko tētahi ina he tango.

$$4x^{2}+4x=5$$

Me tango 5 mai i ngā taha e rua o te whārite.

$$4x^{2}+4x-5=5-5$$

Mā te tango i te 5 i a ia ake anō ka toe ko te 0.

$$4x^{2}+4x-5=0$$

Kei te āhua arowhānui tēnei whārite: ax^{2}+bx+c=0. Me whakakapi 4 mō a, 4 mō b, me -5 mō c i te tikanga tātai pūrua, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.

$$x=\frac{-4±\sqrt{4^{2}-4\times 4\left(-5\right)}}{2\times 4}$$

Pūrua 4.

$$x=\frac{-4±\sqrt{16-4\times 4\left(-5\right)}}{2\times 4}$$

Whakareatia -4 ki te 4.

$$x=\frac{-4±\sqrt{16-16\left(-5\right)}}{2\times 4}$$

Whakareatia -16 ki te -5.

$$x=\frac{-4±\sqrt{16+80}}{2\times 4}$$

Tāpiri 16 ki te 80.

$$x=\frac{-4±\sqrt{96}}{2\times 4}$$

Tuhia te pūtakerua o te 96.

$$x=\frac{-4±4\sqrt{6}}{2\times 4}$$

Whakareatia 2 ki te 4.

$$x=\frac{-4±4\sqrt{6}}{8}$$

Nā, me whakaoti te whārite x=\frac{-4±4\sqrt{6}}{8} ina he tāpiri te ±. Tāpiri -4 ki te 4\sqrt{6}.

$$x=\frac{4\sqrt{6}-4}{8}$$

Whakawehe -4+4\sqrt{6} ki te 8.

$$x=\frac{\sqrt{6}-1}{2}$$

Nā, me whakaoti te whārite x=\frac{-4±4\sqrt{6}}{8} ina he tango te ±. Tango 4\sqrt{6} mai i -4.

$$x=\frac{-4\sqrt{6}-4}{8}$$

Whakawehe -4-4\sqrt{6} ki te 8.

$$x=\frac{-\sqrt{6}-1}{2}$$

Kua oti te whārite te whakatau.

$$x=\frac{\sqrt{6}-1}{2} x=\frac{-\sqrt{6}-1}{2}$$

Ngā Upane mō te Whakaoti i te Pūrua

Ko ngā whārite pūrua pēnei i tēnei nā ka taea te whakaoti mā te whakaoti i te pūrua. Hei whakaoti i te pūrua, ko te whārite me mātua tuhi ki te āhua x^{2}+bx=c.

$$4x^{2}+4x=5$$

Whakawehea ngā taha e rua ki te 4.

$$\frac{4x^{2}+4x}{4}=\frac{5}{4}$$

Mā te whakawehe ki te 4 ka wetekia te whakareanga ki te 4.

$$x^{2}+\frac{4}{4}x=\frac{5}{4}$$

Whakawehe 4 ki te 4.

$$x^{2}+x=\frac{5}{4}$$

Whakawehea te 1, te tau whakarea o te kīanga tau x, ki te 2 kia riro ai te \frac{1}{2}. Nā, tāpiria te pūrua o te \frac{1}{2} ki ngā taha e rua o te whārite. Mā konei e pūrua tika tonu ai te taha mauī o te whārite.

$$x^{2}+x+\left(\frac{1}{2}\right)^{2}=\frac{5}{4}+\left(\frac{1}{2}\right)^{2}$$

Pūruatia \frac{1}{2} mā te pūrua i te taurunga me te tauraro o te hautanga.

$$x^{2}+x+\frac{1}{4}=\frac{5+1}{4}$$

Tāpiri \frac{5}{4} ki te \frac{1}{4} mā te kimi i te tauraro pātahi me te tāpiri i ngā taurunga. Ka whakaiti i te hautanga ki ngā kīanga tau iti rawa e taea ana.

$$x^{2}+x+\frac{1}{4}=\frac{3}{2}$$

Tauwehea te x^{2}+x+\frac{1}{4}. Ko te tikanga, ina ko x^{2}+bx+c he pūrua tika, ka taea te tauwehe i ngā wā katoa hei \left(x+\frac{b}{2}\right)^{2}.

$$\left(x+\frac{1}{2}\right)^{2}=\frac{3}{2}$$

Tuhia te pūtakerua o ngā taha e rua o te whārite.

$$\sqrt{\left(x+\frac{1}{2}\right)^{2}}=\sqrt{\frac{3}{2}}$$

Whakarūnātia.

$$x+\frac{1}{2}=\frac{\sqrt{6}}{2} x+\frac{1}{2}=-\frac{\sqrt{6}}{2}$$

Me tango \frac{1}{2} mai i ngā taha e rua o te whārite.

$$x=\frac{\sqrt{6}-1}{2} x=\frac{-\sqrt{6}-1}{2}$$